U.S. patent application number 13/000252 was filed with the patent office on 2011-05-05 for drive mechanism, drive device, and lens drive device.
This patent application is currently assigned to Konica Minolta Opto, Inc.. Invention is credited to Takashi Matsuo, Atsuhiro Noda.
Application Number | 20110102917 13/000252 |
Document ID | / |
Family ID | 41465819 |
Filed Date | 2011-05-05 |
United States Patent
Application |
20110102917 |
Kind Code |
A1 |
Noda; Atsuhiro ; et
al. |
May 5, 2011 |
DRIVE MECHANISM, DRIVE DEVICE, AND LENS DRIVE DEVICE
Abstract
Provided is a drive mechanism comprising a stationary support
member, a lever member having a displacement input portion for
receiving a moving force from the outside and a bearing portion for
abutting against the support member, so that the lever member
engages with a driven member and swings on the bearing portion
relative to the support member in response to the input of the
moving force to the displacement input portion, thereby moving the
driven member in a predetermined first axis direction, and a
shape-memory alloy actuator for applying the moving force to the
displacement input portion. The drive mechanism is characterized in
that a displacement input member having the displacement input
portion and a bearing member having the bearing portion are formed,
in the lever member, of a material different from that of the lever
member.
Inventors: |
Noda; Atsuhiro; (Ashiya-shi,
JP) ; Matsuo; Takashi; (Suita-shi, JP) |
Assignee: |
Konica Minolta Opto, Inc.
Hachioji-shi, Tokyo
JP
|
Family ID: |
41465819 |
Appl. No.: |
13/000252 |
Filed: |
June 16, 2009 |
PCT Filed: |
June 16, 2009 |
PCT NO: |
PCT/JP2009/060931 |
371 Date: |
December 20, 2010 |
Current U.S.
Class: |
359/811 ;
60/527 |
Current CPC
Class: |
G02B 7/102 20130101;
G02B 7/08 20130101; F03G 7/065 20130101 |
Class at
Publication: |
359/811 ;
60/527 |
International
Class: |
G02B 7/04 20060101
G02B007/04; F01B 29/10 20060101 F01B029/10 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 1, 2008 |
JP |
2008-172226 |
Claims
1.-10. (canceled)
11. A drive mechanism for driving a driven member comprising: a
stationary support member; a lever member which engages with the
driven member and moves the driven member; a bearing member formed
of a material different from that of the lever member, provided on
the lever member, and having a bearing portion for abutting on the
support member; a displacement input member formed of a material
different from that of the lever member, provided on the lever
member, and having a displacement input portion for receiving a
moving force from outside; and a shape-memory alloy actuator for
applying the moving force to the displacement input portion;
wherein the lever member is configured to swing about the bearing
portion due to an input of the moving force to the displacement
input portion.
12. The drive mechanism according to claim 11 wherein the lever
member is formed of a metallic material, and the displacement input
member and bearing member are made of a plastic material.
13. The drive mechanism according to claim 11 wherein the
displacement input member and bearing member are integrally formed
as one intermediate member.
14. The drive mechanism according to claim 13 wherein the lever
member is insert-molded into the intermediate member.
15. The drive mechanism according to claim 11 wherein a linear
actuator is provided as the shape memory alloy actuator and the
actuator bent in a V-shape is wound around the displacement input
portion.
16. The drive mechanism according to claim 11 wherein the shape
memory alloy actuator is installed in such a way that a moving
force in a second axial direction as the moving force is inputted
into the displacement input portion.
17. The drive mechanism according to claim 16 wherein a linear
actuator is provided as the shape memory alloy actuator, and the
actuator is arranged inside a surface perpendicular to a direction
in which the driven member is driven.
18. The drive mechanism according to claim 16 wherein the lever
member is supported at the tip end of the support member on the
bearing portion so that the lever member can swing, and the shape
memory alloy actuator is provided so as to abut the lever member on
the drive member in a non-operation state.
19. A drive device comprising a driven member and the drive
mechanism according to claim 11 to move the driven member in a
predetermined first axis direction.
20. A lens drive mechanism comprising a lens unit as a driven
member and the drive mechanism according to claim 11 as a drive
mechanism to move the lens unit in a direction of optical axis.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a drive mechanism, drive
device, and lens drive device.
BACKGROUND
[0002] In recent years, there has been a drastic increase in the
number of pixels of an image pickup element mounted on a
small-sized portable terminal such as a camera-mounted cellular
mobile telephone. Users expect an image quality and function on the
same level as those of a digital camera to be implemented. To meet
this expectation, the lens used on the portable terminal is
required to have focusing and zooming functions in addition to the
basic image capturing function.
[0003] To have such functions added, it is necessary to provide a
lens drive device for moving the lens in the direction of optical
axis. However, use of a general motor or actuator raises a problem
of increasing the size of the lens drive device.
[0004] By contrast, lens drive devices have been disclosed wherein
a shape memory alloy (hereinafter referred to as "SMA") actuator is
used to reduce the size and weight thereof (Patent Literatures 1
through 3).
[0005] The SMA actuator uses the SMA whose shape is recovered to
the state having been memorized by temperature changes. In Patent
Literatures 1 through 3, self-heating takes place when the SMA is
turned on, and a lens is driven by the force generated when the
shape of the actuator is recovered to the memorized state. The
force generated by the SMA actuator in this case is great enough to
provide a compact and lightweight configuration for the lens drive
device. In the lens drive device disclosed in the Patent
Literatures 1 through 3, the force generated by the SMA actuator is
transmitted to the direction of driving a lens using a lever
mechanism.
PRIOR ART
Patent Literature
[0006] Patent Literature 1: Unexamined Japanese Patent Application
Publication No. 2007-58075 [0007] Patent Literature 2: Unexamined
Japanese Patent Application Publication No. 2007-58076 [0008]
Patent Literature 3: Unexamined Japanese Patent Application
Publication No. 2007-60530
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0009] However, the SMA actuator causes stress to be generated by
phase transformation in a high-temperature environment. Thus, if a
drive device using the SMA actuator is left in a high-temperature
environment for a long time, the force generated by the SMA
actuator continues to be applied to the lever mechanism during this
time. If the portion receiving the force generated by the SMA
actuator is made of a resin material alone as in the case of the
lever member of Patent Literature 3, deformation such as creep may
occur. This deformation leads to a failure in precise control of
the drive device. This may further lead to a complete driving
failure.
[0010] In view of the problems described above, it is an object of
the present invention to provide a drive mechanism, drive device,
and lens drive device characterized by a compact and lightweight
structure and a low production cost, without the drive performances
thereof being deteriorated even when these drive mechanism, drive
device, and lens drive device are left in a high-temperature
environment for a long time.
Means for Solving the Problems
[0011] The object of the present invention can be achieved by the
following Structures.
[0012] 1. A drive mechanism for driving a driven member including:
a stationary support member;
[0013] a lever member having a displacement input portion for
receiving a moving force from outside and a bearing portion for
abutting on the support member so that the lever member engages
with the driven member and swings about the bearing portion
relative to the support member due to an input of the moving force
to the displacement input portion, thereby moving the driven member
in a predetermined first axis direction, and a shape-memory alloy
actuator for applying the moving force to the displacement input
portion; wherein the lever member comprises a displacement input
member equipped with the displacement input portion, and a bearing
member equipped with the bearing portion.
[0014] 2. The drive mechanism described in Structure 1 wherein the
aforementioned lever member is formed of a metallic material, and
the displacement input member and bearing member are made of a
plastic material.
[0015] 3. The drive mechanism described in Structure 1 wherein the
displacement input member and bearing member are integrally formed
as one intermediate member.
[0016] 4. The drive mechanism described in Structure 3 wherein the
lever member is insert-molded into the intermediate member.
[0017] 5. The drive mechanism described in Structure 1 wherein a
linear actuator is provided as the aforementioned shape memory
alloy actuator and this actuator bent in a V-shape is wound around
the displacement input portion.
[0018] 6. The drive mechanism described in Structure 1 wherein the
shape memory alloy actuator is installed in such a way that the
moving force in the second axial direction as the moving force is
inputted into the displacement input portion.
[0019] 7. The drive mechanism described in Structure 6 wherein a
linear actuator is provided as the aforementioned shape memory
alloy actuator, and this actuator is arranged inside the surface
perpendicular to the aforementioned first axis direction.
[0020] 8. The drive mechanism described in Structure 6 wherein the
lever member is supported at the tip end of the support member on
the bearing portion so that the lever member can swing, and the
shape memory alloy actuator is provided so as to abut the lever
member on the drive member in the non-operation mode.
[0021] 9. A drive device including a driven member and the drive
mechanism described in Structure 1 to move this driven member in a
prescribed first axis direction.
[0022] 10. A lens drive mechanism including a lens unit as a driven
member and a drive mechanism described in Structure 1 as a drive
mechanism to move this lens unit in the direction of optical
axis.
Effects of the Invention
[0023] According to the present invention, a displacement input
portion and bearing portion formed as separate members are provided
on the surface of the aforementioned lever member. Accordingly,
this present invention provides a drive mechanism, drive device,
and lens drive device characterized by a compact and lightweight
structure and a low production cost, without the drive performances
thereof being deteriorated even when these drive mechanism, drive
device, and lens drive device are left in a high-temperature
environment for a long time.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 is a plan view schematically showing the major
components of a lens drive device 100 in the first embodiment of
the present invention;
[0025] FIG. 2 is a side view schematically showing the major
components of a lens drive device 100 in the first embodiment of
the present invention;
[0026] FIG. 3 is an explanatory diagram of a lever member 2 in the
first embodiment of the present invention;
[0027] FIG. 4 is a perspective view of a lever member 2 and
intermediate member 24 in the second embodiment of the present
invention; and
[0028] FIG. 5 is a perspective view of a lever member 2 and
intermediate member 24 integrated into one structure in the second
embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0029] The following describes the embodiments of the present
invention with reference to the drawings.
[0030] FIG. 1 is a plan view schematically showing the major
components of a lens drive device 100 in the first embodiment of
the present invention. FIG. 2 is a side view schematically showing
the major components of a lens drive device 100 in the first
embodiment of the present invention. FIG. 3 is an explanatory
diagram of a lever member 2 in the first embodiment of the present
invention.
[0031] The lens drive device 100 mainly includes a lens unit 1
(driven member), lever member 2 for moving the lens unit 1 in the
direction of optical axis AX (first axial direction), SMA actuator
3, base member 4, upper plate 5, parallel plate springs 6a and 6b
and bias spring 7, wherein the lens unit 1 is fitted into the base
member 4. The upper plate 5 and parallel plate springs 6a and 6b
are not illustrated in FIG. 1 for the sake of expediency.
[0032] The base member 4 is fixed onto the member on which the lens
drive device 100 is mounted (e.g., frame or mount substrate of a
cellular mobile telephone), and is the unmovable member
constituting the base of the lens drive device 100. This base
member 4 is formed in a quadrilateral plate, as viewed from the
plane, and is made of a resin material.
[0033] The lens unit 1 is cylindrical and includes an image pickup
lens 10 and a lens drive frame 12 for holding this image pickup
lens 10. The image pickup lens 10 has an objective lens, focus
lens, zoom lens and others, and constitutes an image forming
optical system for a subject with respect to an image pickup
element (not illustrated). The lens drive frame 12 is so-called the
lens frame, and moves in the direction of optical axis AX together
with the image pickup lens 10. A pair of support portions 16 having
an angular difference of 180 degrees in the circumferential
direction are provided in a protruded form on the outer edge of the
top end of the lens drive frame 12.
[0034] The lens unit 1 inserted in the opening of the upper plate 5
is mounted on the base member 4. To put it in greater detail, a
pair of support portions 16 is arranged in the vicinity of a pair
of diagonals of the base member 4 (FIG. 1). The parallel plate
springs 6a and 6b are fixed onto the base member 4 and upper plate
5, and the lens unit 1 is fixed to these parallel plate springs 6a
and 6b. This arrangement allows the lens unit 1 to be supported
displaceably with respect to the base member 4 and others, and the
degree of freedom in displacement is regulated in the direction of
optical axis AX. The upper plate 5 can be fixed on the base member
4 through the stay and others (not illustrated) or can be formed
integral with the base member 4. The upper plate 5 is an unmovable
member in the same manner as the base member 4.
[0035] The lever member 2 engages with the lens unit 1 through the
support portions 16, whereby the lens unit 1 is driven in the
direction of optical axis AX.
[0036] As shown in FIG. 1, the lever member 2 is mounted on the
side of the lens unit 1. To put it more specifically, the lever
member 2 is mounted on one of the corners of the base member 4
except for the corner wherein the support portions 16 of the lens
unit 1 are located. In this embodiment, to reduce the size of the
lens drive device 100, the lever member 2 is formed of a metallic
plate stock and is arranged in a gap between the rectangular sides
of the lens unit 1 and base member 4, as shown in FIG. 1.
[0037] The following describes the lever member 2 with reference to
FIG. 3. FIG. 3a is a plan view showing the lever member 2. FIG. 3b
is a side view showing the lever member 2. FIG. 3c is a front view
showing the lever member 2 as viewed from the first extension
22.
[0038] As shown in FIG. 3, the resin-made first extension 22 and
second extension 23 are bonded onto the surface of the lever member
2. In FIG. 3, 2a is a displacement input portion, 2b is a
displacement output portion, and 2c is a bearing portion.
[0039] The first extension 22 is used to apply an SMA wire 3 to the
lever member 2. The displacement input portion 2a is designed in a
complicated shape consisting of a plurality of curvature radiuses
in order to minimize the friction at the portion in contact with
the SMA wire 3. The first extension 22 provides a displacement
input portion of the present invention.
[0040] The lever member 2 is perpendicular to the optical axis AX
and is supported around the axial line extending in the direction
wherein a pair of the aforementioned support portions 16 are
arranged (in the vertical direction in FIG. 1) so that the lever
member 2 can swing. The second extension 23 is in contact with the
lever leg 8, and provides a fulcrum when the lever member 2 swings.
The bearing portion 2c in contact with the tip end of the lever leg
8 (hereinafter referred to as "lever support 8a") is shaped to have
complicated flexures in order to minimize friction with the level
support 8a. The second extension 23 is a bearing member of the
present invention.
[0041] As described above, the first extension 22 and second
extension 23 must be designed in a small and complicated
configuration. In the present embodiment, the first extension 22
and second extension 23 are produced by molding the resin material.
It should be noted, however, that the material forming the first
extension 22 and second extension 23 is not restricted to resin.
For example, the material forming the first extension 22 and second
extension 23 can be produced by casting a metallic material.
[0042] As shown in FIG. 2a, the lever member 2 is designed in an
inverted L-shape, as viewed from the side. Since the bearing
portion 2c of the second extension 23 is supported at the tip end
of the lever leg 8 standing on the base member 4, the lever member
2 is supported on the base member 4. The lever support 8a is
designed in an approximately cylindrical shape that extends in the
direction perpendicular to the direction of optical axis AX (in the
direction perpendicular to the paper surface of FIG. 2a). This
design ensures the lever member 2 to be supported so as to swing
about the axial line perpendicular to the direction of optical axis
AX using the lever support 8a as a fulcrum.
[0043] As shown in FIG. 1, the lever member 2 branches off in two
from the second extension 23 toward both sides of the lens unit 1.
Each of the branches comes closer to the outer peripheral surface
of the lens unit 1 and extends uniformly to enclose 50 percent of
one side of the lens unit 1 as a whole. Each of the displacement
input portions 2b on both the tip ends of the lever member 2
reaches each of the support portions 16 of the lens unit 1. Then
the SMA actuator 3 (to be described later) is applied to the first
extension 22 arranged on the surface of the lever member 2. The
lever member 2 swings when the moving force F1 in the direction
perpendicular to the direction of optical axis AX (in the direction
of second axis, i.e., in the longitudinal direction of FIG. 2) has
been inputted into the displacement input portion 2a wherein the
SMA actuator 3 is applied. The swing'operation causes the tip end
of the lever member 2 to be displaced in the direction of optical
axis AX. Then the displacement input portion 2b engages with each
of the support portions 16 so that the drive force in the direction
of optical axis AX is given to the lens unit 1.
[0044] As described above, in the present embodiment, the moving
force F1 is inputted to the lever member 2 made of a metallic
material through the displacement input portion 2a, and the drive
force in the direction of optical axis AX is given to the lens unit
1 wherein the bearing portion 2c provided on the lever member 2 is
used as a fulcrum.
[0045] The metallic plate selected for use in the lever member 2 is
required to have such thickness and strength as to ensure that the
deformation is not caused by the external force applied to the
lever member when the lens unit 1 is driven. The metallic material
that can be used includes iron, brass, and aluminum, for
example.
[0046] The SMA actuator 3 provides the lever member 2 with the
moving force F1, and is exemplified by a linear actuator made of
the wire of the shape memory alloy (SMA) such as Ni--Ti alloy. This
SMA actuator 3 elongates when a prescribed tension is given at a
low temperature with a low elastic modulus (martensite phase). If
heat is applied in the elongated state, the SMA actuator 3 shifts
to the state of a high elastic modulus (austenite phase) so that
the SMA actuator 3 goes back to the original state from the
elongated state (recovery of shape). In the present embodiment, the
aforementioned phase transformation is carried out when the SMA
actuator 3 is heated by the application of electric power. To be
more specific, since the SMA actuator 3 is a conductor having a
prescribed resistance, Joule heat is generated when power is
supplied to the SMA actuator 3, and transformation is carried out
from the martensite phase to the austenite phase by self-heat
generation based on the Joule heat. Thus, a first electrode 30a and
second electrode 30b for heating by power application are fixed on
both sides of the SMA actuator 3. The first electrode 30a and
second electrode 30b are fastened to a prescribed electrode fixing
section provided on the base member 4.
[0047] As shown in FIG. 1, the SMA actuator 3 is wound around the
displacement input portion 2a of the lever member 2 so as to be
folded back in a V-shape. This arrangement allows the SMA actuator
3 to be heated by the application of electric power through the
electrodes 30a and 30b. When the SMA actuator 3 has been operated
(contracted), the moving force F1 is supplied to the lever member
2, and the lever member 2 swing by the moving force F1.
[0048] The electrodes 30a and 30b are arranged in the vicinity of
the support portions 16 of the lens unit 1 in the base member 4.
Lengths are set at the same level from the electrodes 30a and 30b
to the turnaround point in the SMA actuator 3. This provides the
same amounts of expansion and contraction of the SMA actuators 3 on
both sides of the displacement input portion 2a, and prevents
abrasion from occurring between the lever member 2 and SMA actuator
3 when the SMA actuator 3 has operated.
[0049] The displacement input portion 2a is formed in the V-shape,
and the SMA actuator 3 is applied to the displacement input portion
2a so as to fit therein, whereby the SMA actuator 3 is stably
suspended on the lever member 2.
[0050] The bias spring 7 biases the lens unit 1 in the direction of
optical axis AX, i.e., in the direction opposite to the direction
in which the displacement input portion 2b of the lever member 2 is
moved by the operation of the SMA actuator 3. The bias spring 7 is
made of the compressed coil spring having a diameter approximately
the same as the edge size of the lens drive frame 12. One side
(lower end side) abuts on the peaked surface of the lens drive
frame 12. The other side (upper end side) of the bias spring 7
abuts on the unmovable portion N such as the inner surface of a
cellular mobile telephone housing.
[0051] The potency of the bias spring 7 is assumed to be smaller
than the moving force F1 given to the lever member 2. When the SMA
actuator 3 is not operating, the lens unit 1 is pressed against the
base member 4. When the SMA actuator 3 has operated, the lens unit
1 moves in the opposite direction (toward the objective) against
the pressure of the bias spring 7. To be more specific, the bias
spring 7 provides the lens unit 1 with a bias load for returning
the lens unit 1 to the home position when the SMA actuator 3 is not
heated by the application of electric power.
[0052] In the non-operation mode, the line length of the SMA
actuator 3 is determined so that tension will be given to the SMA
actuator 3 by receiving the pressure of the bias spring 7 working
through the lens unit 1 (support portion 16) and lever member 2. To
be more specific, the line length is determined so that the
displacement input portion 2b of the lever member 2 abuts on (is
pressed against) the lens unit 1 (support portion 16),
independently of the operation status. This arrangement allows the
lever member 2 to be supported on the tip end of the lever leg 8 so
that the lever member 2 can swing, without directly connecting the
lever leg 8 to the lever member 2, in the present embodiment. When
the SMA actuator 3 is working, the displacement is quickly
transferred to swing the lever member 2.
[0053] In the lens drive device 100, when stopping the SMA actuator
3 (at the time of elongation) which is not heated by the
application of electric power, the lens unit 1 is pressed against
the base member 4 by the pressure of the bias spring 7, whereby the
lens unit 1 is held at the home position (FIG. 2a). In the
meantime, when the SMA actuator 3 has operated (contracted), the
moving force F1 is supplied to the displacement input portion 2a of
the lever member 2, and the lever member 2 swings. This swing
operation causes the displacement input portion 2b to be moved in
the direction of optical axis AX (FIG. 2b). As a result, the lens
unit 1 is supplied with the drive force to the objective side and
the lens unit 1 moves against the pressure of the bias spring 7. In
this case, the current applied to the SMA actuator 3 is placed
under control so that the potency of the moving force F1 is
regulated. As a result, the displacement of the lens unit 1 is
regulated.
[0054] When the power supply to the SMA actuator 3 is stopped (or
voltage is reduced to a prescribed level) and the SMA actuator 3 is
cooled so that the martensite phase is restored, the moving force
F1 turns off, and the lens unit 1 is reset by the pressure of the
bias spring 7 to the home position by moving in the direction of
optical axis AX. Thus, the lens unit 1 can be displaced in the
direction of optical axis AX by the power on-off operation for the
SMA actuator 3. Further, the current supplied to the SMA actuators
3a and 3b is placed under control, and the potency of the moving
force F1 is regulated, whereby the displacement of the lens unit 1
can be adjusted.
[0055] As described above, in the lens drive device 100 using the
drive mechanism of the present invention, the lens unit 1 can be
moved effectively in the direction of optical axis AX in response
to the operation of the SMA actuator 3. Further, even when the lens
drive device 100 has been left in a high-temperature environment
for a long time, a creep does not occur since the lever member 2 is
made of metal. Thus, even when the lens drive device 100 has been
left in a high-temperature environment for a long time, the lever
member 2 is not deformed by the force generated by the SMA actuator
and the drive performance is not deteriorated. Further, since the
lever member 2 is formed by working the metallic plate, the lens
drive device 100 can be designed in a compact configuration
characterized by lower production costs.
[0056] The following describes the drive mechanism of the second
embodiment with reference to FIGS. 4 and 5.
[0057] In the second embodiment, the drive mechanism uses the
intermediate member 24 wherein the displacement input portion 2a
and bearing portion 2c are formed in one integral member. The drive
mechanism also uses the lever member 2 and intermediate member 24
formed in one integral member, as shown in FIG. 5.
[0058] FIGS. 4a and 4c are the perspective views of the lever
member 2. FIG. 4a is a perspective view, as seen from the
displacement input portion 2a. FIG. 4c is a perspective view, as
seen from the displacement input portion 2c. FIGS. 4b and 4d are
the perspective views of the intermediate member 24. FIG. 4b is a
perspective view, as seen from the displacement input portion 2a.
FIG. 4d is a perspective view, as seen from the displacement input
portion 2c. FIG. 5 is a perspective view representing that the
lever member 2 and intermediate member 24 are formed into one
integral piece.
[0059] Similarly to the case of the first embodiment, the lever
member 2 of the second embodiment is formed by working the metallic
plate. This is slightly different from the lever member 2
illustrated in FIGS. 4 and 5. The lever member 2 of the second
embodiment has the same function as that of the first
embodiment.
[0060] The intermediate member 24 is formed by resin, and is
provided with the displacement input portion 2a, bearing portion
2c, and groove 24a. When the lever member 2 is moved in the
direction shown by an arrow in the drawing and is pressed into the
groove 24a, the lever member 2 and intermediate member 24 are made
into one integral piece, as shown in FIG. 5. Thus, similarly to the
case of the first embodiment, the displacement input portion 2a and
bearing portion 2c made of resin are provided on the surface of the
lever member 2.
[0061] If the shape and position are made equivalent to those of
the displacement input portion 2a and bearing portion 2c, the lever
member 2 of the second embodiment can also be incorporated into the
lens drive device 100 described with reference to FIGS. 1 and 2.
Similarly, the lens unit 1 can be driven. The operation of the lens
drive device 100 is the same as that of the first embodiment, and
the description is omitted.
[0062] In the first embodiment, the first extension 22 and second
extension 23 are mounted on the lever member 2. In the present
embodiment, by contrast, it is only required to mount the
intermediate member 24 alone. This arrangement reduces the number
of parts and the number of man-hours for assembling. Further, if
the lever member 2 is formed by being insert-molded into the
intermediate member 24, the assembling process is simplified, and
production costs are reduced.
[0063] Further, the present embodiment enhances the precision in
relative positions of the displacement input portion 2a and bearing
portion 2c. This reduces variations in the fluctuation of the
displacement of the lens unit 1 with respect to the moving force
F1, with the result that control of the drive device is
facilitated.
[0064] The present invention described above provides a drive
mechanism, drive device, and lens drive device characterized by a
compact and lightweight structure and a low production cost,
without the drive performances thereof being deteriorated even when
these drive mechanism, drive device, and lens drive device are left
in a high-temperature environment for a long time.
DESCRIPTION OF REFERENCE NUMERALS
[0065] 1. Lens unit [0066] 2. Lever member [0067] 2a. Displacement
input portion [0068] 2b. Displacement output portion [0069] 2c.
Bearing portion [0070] 3. SMA actuator [0071] 4. Base member [0072]
5. Upper plate [0073] 6. Plate spring [0074] 7. Bias spring [0075]
8. Lever leg [0076] 10. Lens [0077] 12. Lens drive frame [0078] 16.
Support portion [0079] 21. Arm [0080] 22. First extension [0081]
23. Second extension [0082] 24. Intermediate member [0083] 24a.
Groove [0084] 30. Electrode [0085] 40. Extension [0086] 100. Lens
drive device
* * * * *